Security

What is Transaction nonce?

A transaction nonce is a value used to make a transaction or request unique within a particular account or protocol. Some systems use sequential account counters; others use one-time challenge values. The exact rule depends on the protocol and must be enforced by the verifier.

Nonces help prevent replay when they are bound to the right signer, chain, action, and expiration and are consumed atomically. A nonce included in a message is not protective if the server does not check its freshness and record its use.

Different protocols define nonce scope differently. Implement the protocol's rules precisely, including concurrent requests and recovery after a timeout, rather than assuming every nonce is a simple account counter.

Definitions are educational and general. Nothing here is financial, legal or tax advice, and regulatory descriptions summarise frameworks that change — check the current rules for your jurisdiction before relying on them.